Thread: tdi 300

there is a tool that go on your socket,
like the old school compasss, with 360 dec on it.
after you torque stage two (s2) to 40Nm
then turn the bolt, 60 dec within a circle. (s3)
then again, then turn the bolt, another, 60 dec within a circle (s4)
then again, then turn the bolt, another, 20 dec within a circle (s5) M12 /140 bolts
eg.
full 360
1/2 180 dec
1/4 90 dec
1/8 45 dec

hope this helps.

...and make sure you remember to put the air cleaner bracket back on before tightening all the bolts down in sequence. First time around I forgot.

Cheers, Iain

I take it that you want to know what torque corresponds to each tightening stage.

The problem is that bolt tightening torque is not reliably converted to bolt tension/clamping force, except at low values of torque. If it was, manufacturers would state torque values. The reason is that friction increases at too high a rate with increasing bolt tension and friction coefficients vary too much.

300Tdi's often suffer head gasket problems from loss of bolt clamping force, especially if they have ever suffered from overheating. So it is best to follow the angle tightening procedure.

If you are replacing a blown gasket, following an overheating episode, you are best advised to have the hardness of the head tested to determine if it has soft spots. If it is soft, the head can be re-heat treated. This is better than suffering further head gasket failures.

Edit: If you can't find a 1/2" square drive angle gauge for your sockets, you can make do with a piece of cardboard that has a hole to slip over your socket and the appropriate angles marked as radial lines from the centre of the hole. Then bend up a wire pointer to fit your socket bar. It is best to have an assistant who can position/zero the cardboard to the wire pointer and hold it in position while you tighten the bolt by the required part turn.

The head tensions on the 300Tdi must be done at torque angle after the initial torque setting, 45Nm, 60deg, 60deg and a further 20deg for the central rows of long bolts.
After doing the first 45nm stage, you MUST go over them again at the same torque setting as you will find the first 5 or 6 ones you did will be loose after all the others were done. Then to achieve 60deg WITHOUT the angle gauge, you mark the head with a marker pen at the point of one of the bolt heads, then mark the bolt point. Rotating this bolt around so the next bolt point lines up with the mark on the head is 60degrees, and so on. (6 points = 60 degrees apart = 360degrees)

JC